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View a LW4 file online, free

Open and read .LW4 files online. View source, logs and text with syntax highlighting, search and line numbers, free.

Drop your .LW4 file here

Opens your .LW4 file right here.

Choose file
Up to 50 MB · 160+ text and code extensions
Instant. Opens in seconds
No sign-up. Just open it
100% free. No limits on use

What you get for a .LW4 file

We don't have a dedicated viewer for this format, so we identify and inspect it instead — honestly, only what can be read from the file.

01

Drop your .LW4 file

Choose it or drag it in. It's read right here in your browser.

02

We identify it

We read the magic bytes to tell what the file really is, its MIME type, and whether the name matches the contents.

03

See the details

Any metadata we can extract (dimensions, EXIF/GPS, document author and dates), a hex view, plus readable text and strings found inside.

What is a .LW4 file?

Plain text that programs, servers and people write every day.

A .LW4 file is a data file created by John McKernon Software for use with Lightwright. It contains information related to stage lighting design and documentation. Users can open and manage these files specifically within the Lightwright application.

Programs that open .LW4 files

Windows
Lightwright
macOS
Lightwright
.LW4 format details
DeveloperJohn McKernon Software

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Every viewer is free to use.

Frequently asked questions

Is my .LW4 file uploaded anywhere?

No. The file is read and highlighted for you.

Why do some characters look wrong (é, ł)?

That usually means the file was saved in one encoding and opened in another. We detect UTF-8, UTF-16 and the Windows-1250/1252 code pages automatically and show which one was used.

Can it handle huge log files?

Yes, up to 50 MB. Only the lines on screen are drawn, so scrolling stays smooth. Syntax colours are switched off for files over 1.5 MB to keep things fast.

How do the log level filters work?

We find levels like ERROR, WARN, INFO and DEBUG on each line. Lines without a level, such as stack traces, stay with the entry above them, so filtering to errors keeps the full trace.

Can I edit the file?

This is a viewer. To change code, download it or copy it into your editor. Converting encodings and line endings is planned.

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